Hydraulic draft gear



March 30, 1965 w. cs. PRICE ETAL HYDRAULIC DRAFT GEAR 4 Sheets-Sheet lFiled March 26, 1962 i Ill @DIW ATTORNEY March 30, i965 w. G. PRICE ETAL3,][75699 HYDRAULIC DRAFT GEAR Filed Maron ze, 1962 4 sheets-sheet 2March 30, 1965 w. G. PRICE ETAL 3,175,699

, HYDRAULIC DRAFT GEAR Filed March 26, 1962 4 Sheets-Sheet 5 7 Taf/VE?March 30, 1965 w. G. PRICE ETAL HYDRAULIC DRAFT GEAR 4 Sheets-Sheet 4Filed March 26, 1962 proximately equivalent to the amount of energy thatit can absorb during a closure movement of the gear. addition resilientdraft gears, such as rubber cartridges, springs, etc., have thedisadvantage of returning a major part of the energy which was initiallyapplied to the draft gear by recoil to the train or cars.

shock absorber of FIGURE 3;

nied States Patent 3,175,699 HYDRAULIC DRAFT GEAR William G. Price andGeorge lE. Frederick, Jr., South Bend, Ind., assignors, by mesneassignments, to ACF Industries, Incorporated, New York, NSY., acorporation of New .Iersey Filed Mar. 26, 1962, Ser. No. 182,423 3Claims. (Cl. 213-43) This invention relates to shock absorbing units foruse on railway vehicles to absorb impact shocks during shunting and/oitoprovide an energy dissipative type draft connection between vehiclesduring running.

The impact cushioning ability of the draft gear is ap- As for energydissipative devices in the past, they have It is also true that therehave been It is therefore a More particularly, it is an object of thisinvention to provide a structurally sound hydraulic shock absorber for astandard draft gear pocket which is capable of controlled automaticrecovery from a compressed condition.

It is another object to provide an all hydraulic draft gear so that ahigh initial resistance to buff or draft forces is developed at theinception of such forces, which resistance is maintained at asubstantial value throughout the duration of such force.

Still another object is to snub the return of said hydraulic drafti gearfrom its compressed condition tc eliminate recoil forces in thehydraulic draft gear.

A further object is to prevent rupture of the hydraulic draft gear uponthe occurrence of excessive buff and draft forces.

Other objects and features of our invention will become apparent from adetailed description of the device which follows with reference to theaccompanying draw ings wherein:

FIGURE l is a plan view of a railway car sill structure mounting acoupler and an Iall hydraulic draft gear of the present invention;

FIGURE 2 is a side v-iew of the assembly of FIG- 55 URE l;

FIGURE 3 is a sectional View of a shock absorber designed in accordancewith the present invention;

FIGURES 4 and 5 are views of the end plates of the 0 FIGURE 6 is asectional view of a modified shock absorber; and

FIGURE 7 is a sectional view showing another arrangement for themodified shock absorber of FIGURE 6.

Referring now to FIGURE 1, there is shown a railway car center sill 10having a striker face 12 and a center filler 14 between which is found adraft gear pocket 16. A coupler 18 is passed through an opening 20 andbears, as at 22, against a follower plate 24 which in turn bears againststop flanges 26 provided by the rearward structure of the striker 12thereby preventing movement of the follower plate 24 leftwardly from theposition shown in FIGURES 1 and 2.

The coupler has la draft key 28 which is passed through a slot 30 of thecoupler 18 and through an elongated opening 32 in a yoke 34. The yoke 34surrounds a shock absorber 36 centrally of the stop flanges 26 and asimilar peripheral stop 38 formed with the center ller 14.

When undergoing a buff load the coupler displaces the plate 24 tocompress the shock absorber against stops 38; whereas a draft force oncoupler 18 cau-ses the yoke 34 to compress the shock absorber againststops 26.

As for the shock absorber details, two general types are hereinafterdiscussed, namely a hydraulic shock absorber with an air return chamberand a hydraulic unit with a spring return. However, both of these unitsincorporate several common features such as end plate design, seeFIGURES 4 and 5, and a capacity to cushion forces being applied to carshaving a wide range of load conditions. This latter feature isaccomplished by incorporating a metering pin into each of the variousunits which is capable of obtaining the above results. In more detail,it is our intent to provide a metering pin for each of the units thattakes into consideration the minimum load and the maximum load of therailroad car, and such a pin could be described as one which has a steptaper form. This means that the metering pin closes the orifice at onerate for a lightly loaded car and at another or faster rate with aheavier car load.

With regard to the air return type of shock absorber as shown by FIGURE3, a cylinder 44 is shown having an integral wall 46 at one end throughwhich the metering pin 41 is mounted, as at 48. The wall 46 -is formedas a rectangular structure that fits within the draft gear pocket suchthat it is in contact with one of the sill stop means above mentioned.The cylinder 44 is also provided with an open end 50 through which atubular member 52 may be inserted. At one end of member 52 a wall 54 ismounted, said Wall having an orifice 56, which orifice is operativelyassociated with pin 41. The member 52 is held centered in the cylinderby a bearing 5S, and the cylinder has its open end closed around member52 by means of a packing gland 60 held in said open end by a gland nut62. Behind the wall 54 within member 52 is a iioating piston 64. Themember 52 is closed by an end cap 66 which is also formed as arectangular structure to cooperate with the stops of the draft gearpocket as does wall 46. In addition, member 52 is provided with acharging valve 68, as seen in FIGURE 4, so that proper return pessuremay be realized and that air leakage may be compensated for.

The cylinder 44 is substantially filled with an incompressible Huid;whe-reas the tubular member 52 is charged with a compressible fluid,such as air by means of valve 68. The floating piston 64 separates Athetwo fluids. Between the wall 54 and the piston 64 the tubular member 52is provided with a plurality of annularly spaced bores 76 about which anannular collar 72 having a metering orioe 74 is placed such thatcompression of the shock absorber ports fluid to an annular chamber 76by displacing the collar 72, and extension of the unit, -by release ofthe stored energy in the compressible iiuid, causes the collar to coverthe bores 70 and meter the ow from chamber 76 to within the tubularmember 52. This effectively snubs the extension of the shock absorber.

As for the shock absorbers of FIGURES 6 and 7, they represent thepreferred shock absorber arrangement in that return forces of the springare not as intense as in the compressed air lunit `of FIGURE 3. Withreference to the unit shown in FIGURE 6, a tubular member 78 is providedhaving integral radiating iianges 80 at one end thereof. A ller plug S2is joined to said tubular member 78 centrally of the flanges 0, as bythe screw threads S4 shown in FIGURE 6; `and plug S2 mounts the meteringpin 42 along the central axis of tube 78. A rod 86 is reciprocaliymounted within member 78 as by a bearing seal 88, and rod 36 has arectangular plate 90 joined therewith. A tapped hole 91 shown in FIGURE7 .may be provided for joining plate 90 to rod 86. Plate 90 and flangeare operatively associated with the stops 26 and 38 of the draft gearpocket 16. The diameter of rod 86 is such as to form an `annular space92 between it and the inner diameter of tube 78; and the rod 86 isprovided with a piston face 94 having centrally located oriiice 96opening into a bore 98 within the rod 86 adjacent its piston face. Thebore 98 is provided with radial passages 100, which passages communicatethe bore 93 with space 92 about the rod S6. In addition, a sleeve 102 ismounted to tube 78 Within space 92, and sleeve 102 in turn mounts acompressible member 104, such as a neoprene sponge rubber, occupying amajor portion of the space 92. The compressible metmber should be madeof a material capable of operation throughout a temperature range offrom -50 F. to 200 F. In order that the compressible member may beprotected an impervious membrane 106 encloses the member.

In the shock absorber shown in FIG. 7, a rod 87 is provided with apiston 95 at one end adapted to slide in a cylinder or tube 79. Tube 79is provided with a ange 81 and an end wall 83 in which a variablytapered metering pin 43 is removably mounted. A compressible material105 similar to material 104 in FIG. 6, occupies chamber 93. Sleeve 103forms the bearing seal between rod 87 and tube 79. A nozzle or valvebody 111 is held by a retaining ring 109 in a central aperture of piston95. Valve body 111 is formed with a seat 107 and with a plurality ofaxial passages 112 leading to groove or opening 113. Opening 113 isnormally closed by valve spool 115 having notched portions 117 at theouter end thereof and arranged to abut sleeve 119 at its other end.Sleeve 119 has openings 121 to the bore 99 and chamber 93. Valve spool115 has a stepped coniiguration providing an annular pressure responsiveface 110 whose `area is such as to enable a predetermined pressure inchamber 129 to overcome the force of spring 123, which acts againstbearing plate 125. Plate 125 is threaded to sleeve 119 and is lockedthereto by set screw 127.

When a load or force is applied to the shock absorber,

piston moves further into chamber 129 and during the course of travelmetering pin 43 enters orifice 97 and controls the flow Ithrough it intochamber 93. If excessive pressure is developed in chamber 129, due toexcessive buff or draft forces, the iiuid in passages 112 acting on face110 of valve spool 115 overcomes the force of spring 123 on spool 115and moves spool 115 so as to place passages 112 in communication throughtubular network 108 with chamber 93. The path between chambers 129 and93 is via passages 112, opening 113, notches 117, opening 121 andpassage 101. The length of spool 115 is such as to provide bearingsupport for the spool when it moves to the left to open notches 117 toopening 113. Thus, Ithe tubular network 108 and spool 115 and theirassorted elements form a spring loaded bypass valve that relieves excesspressure within chamber 129.

In order to re-turn the shock absorber to its normal extended positionafter buff or draft forces are relieved, a spring 114, as seen in FIGURE6, is provided, which spring is compressed between plate 90 and ashoulder 116 of the tube 78. A similar shoulder and spring may beprovided with the unit of FIGURE 7. Such `a spring return is, however,aided by the comprcssible member 104 or 105 which forces the fluid fromspace 92 or 93 `through passages or 101 and bore 93 or 99 into orifice96 or 97 and out into tube 7S or 79.

It may be readily appreciated that other structural variations tmay beencompassed by our invention, Therefore, we do not intend to be limitedby the above description, but rather by `the appended claims.

We claim:

1. In a railroad draft gear pocket, a kinetic energy absorbing devicecomprising:

a fluid containing cylinder;

a piston dividing said cylinder into two variable volume chambers, saidpiston having a tubular extension with radial passageways which inassociation with passageways in said piston provide fluid communicationfor said variable volume chambers;

a fluid pressure responsive means in one of said variable volumechambers, which iiuid pressure responsive means controls ejection of auid from one of said variable volume chambers upon relief of loads onsaid energy absorbing device;

a Spring loaded valve in said tubular extension of said piston torelieve excess pressures in the other of said variable volume chambersby opening one of the passageways in said piston to permit an increasediiuid flow therethrough; and

means mounting said energy absorbing device in an operative arrangementwithin said draft gear pocket.

2. A kinetic energy absorbing device according to claim l furthercomprising a step taper form metering pin removably mounted within saidcylinder in axial alignment with one of the passageways in said pistonto close the area of the passageway at a varying rate.

3. In a railroad draft gear pocket, a kinetic energy absorbing devicecomprising:

a fluid containing cylinder;

a piston dividing said cylinder into two variable volume chambers, saidpiston having a tubular extension with passageways in said piston whichprovide iiuid communication for said variable volume chambers;

a iiuid pressure responsive means in one of said variable volumechambers, which iuid pressure responsive eans controls ejection of afluid from one of said variable volume chambers upon relief of loads onsaid energy absorbing device;

a spring loaded valve in said tubular extension of said piston torelieve excess pressures in the other of said variable volume chambersby opening one of the passageways in said piston to permit an increasedfluid flow therethrough; and

means mounting said energy absorbing device in an operative arrangementwithin said draft gear pocket.

References Cited in the file of this patent UNITED STATES PATENTS1,955,349 Stevens Apr. 17, 1934 2,841,294 Hendrickson et al. July l,1958 2,909,292 Hendrickson c Oct. 20, 1959 2,914,195 Pawling Nov. 24,1959 2,963,175 Thornhill Dec. 6, 1960 2,994,442 Frederick Aug. 1, 1961

1. IN A RAILROAD DRAFT GEAR POCKET, A KINETIC ENERGY ABSORBING DEVICECOMPRISING: A FLUID CONTAINING CYLINDER; A PISTON DIVIDING SAID CYLINDERINTO TWO VARIABLE VOLUME CHAMBERS, SAID PISTON HAVING A TUBULAREXTENSION WITH RADIAL PASSAGEWAYS WHICH IN ASSOCIATION WITH PASSAGEWAYSIN SAID PISTON PROVIDED FLUID COMMUNICATION FOR SAID VARIABLE VOLUMECHAMBERS; A FLUID PRESSURE RESPONSIVE MEANS IN ONE OF SAID VARIABLEVOLUME CHAMBERS, WHICH FLUID PRESSURE RESPONSIVE MEANS CONTROLS EJECTIONOF A FLUID FROM ONE OF SAID VARIABLE VOLUME CHAMBERS UPON RELIEF OFLOADS ON SAID ENERGY ABSORBING DEVICE; A SPRING LOADED VALVE IN SAIDTUBULAR EXTENSION OF SAID PISTON TO RELIEVE EXCESS PRESSURES IN THEOTHER OF SAID VARIABLE VOLUME CHAMBERS BY OPENING ONE OF THE PASSAGEWAYIN SAID PISTON TO PERMIT AN INCREASED FLUID FLOW THERETHROUGH; AND MEANSMOUNTING SAID ENERGY ABSORBINT DEVICE IN AN OPERATIVE ARRANGEMENT WITHINSAID DRAFT GEAR POCKET.